1. Field of the Invention
The present disclosure relates to the field of prosthetic devices. More specifically, the invention relates to a prosthetic eye with a natural blink. Even more specifically, the present disclosure relates to a mechanism integrable into a prosthetic eye that effectuates a normal blink which provides a normal facial appearance for people with facial defects.
2. Description of the Related Art
Facial defects can be caused by congenital anomalies, trauma, or cancer. One possible facial defect is the loss of an eyelid or entire eye socket. The treatment is an orbital exenteration, a procedure where the eyelids and all orbital contents are removed. Eleven thousand people in the U.S. require an orbital exenteration every year. (P. Lee, Wang, C. C., & Adamis, A. P., “Ocular neovascularization: An epidemiological review,” Survey of Ophthalmology, vol. 43, pp. 245-269, 1998.)
An orbital prosthesis can be created to protect sensitive skin against outside stimuli and to prevent an individual from being perceived as abnormal. While current orbital prostheses are able to replace absent facial anatomies with artificial eyes and eyelids, they are immobile and thus not truly lifelike. For patients who have already suffered the severe loss of facial anatomy and have undergone an orbital exenteration, many are also impacted psychologically when they are perceived as abnormal.
Orbital prostheses consisting of silicon eyelids and acrylic eyes are used to aesthetically cover a defect in the soft tissue of the orbit. These orbital prostheses are composed of medical grade silicone and methacrylates. Acrylic is implemented in the eyeball portion of the prosthetic and silicone is implemented in the area surrounding the eyeball (lids, brow) to mimic the appearance of the native facial tissue. Silicones are soft and flexible, maintain body temperature, and can be stretched to transparency. Furthermore, fine skin features such as hair and folds are easily introduced, making silicone the ideal material. The prosthetic anchorage can then be achieved through the use of adhesives.
Although these prostheses are the current gold standard in protecting sensitive skin against outside stimuli while mimicking the appearance of the healthy eye, they are immobile and at best create an appearance of facial paralysis. Facial paralysis and other forms of facial disfigurement attract attention and can lead to greater levels of anxiety, depression, maladaptive behavior, and reduced emotional well-being [1]. (Fu L, Bundy C, Sadiq S A. “Psychological distress in people with disfigurement from facial palsy,” Eye (Lond). 2011; 25:1322-1326.) Orbital prosthesis that are static are not successful in fully overcoming the appearance of abnormality and reducing the associated psychological distress.
Although these types of orbital prosthesis appear lifelike, they do not have a blinking capability. Thus, individuals using the prosthesis can be perceived as abnormal as they are unable to blink with their orbital prosthesis. Because the orbital prosthesis does not blink, patients become prone to daily psychological trauma in addition to suffering from a loss of facial function. Thus, in order to improve a patient's quality of life, a prosthetic eye with a natural blink is needed to remove the perception of abnormality.
In addition, an orbital prosthesis with a blink tempo that can be controlled is needed to allow future synchronization with the contralateral eye. Further, the device should be easily integrated with current prosthesis designs during fabrication, should fit inside the orbital cavity, and should be non-invasive and safe for patient use. This will allow the patient to continue with their daily routine that they already follow with a standard prosthesis.
Finally, the improved device should be convenient for an ocularists to modify for different sized orbits so that the components in the device that depend on patient size can be fabricated and shaped to any given patient.